The invention relates to the field of medical devices, their use and manufacture, and more specifically to medical devices and techniques for diagnosing intestinal ischemia or bowel ischemia.
Intestinal ischemia or bowel ischemia is a term used to describe the result of a variety of disorders that cause insufficient blood flow to the gastrointestinal tract. Ischemia can be localized to a relatively small part of the small intestine or large intestine, or it may be widespread and involve both types of intestines. Moreover, ischemic necrosis (i.e., localized death of living cells) of the intestine can be superficial, involving mucosa (inner lining) to full thickness transmural necrosis. Intestinal ischemia can manifest with symptoms ranging from a mild, short-lived abdominal pain, to bloody diarrhea or a more serious situation that may require surgery.
There are several causes for intestinal ischemia. The most common cause is diminished intestine perfusion resulting from low cardiac output. It is often seen in patients with cardiac disease or in patients with prolonged shock of any etiology. Another cause of intestinal ischemia is an occlusive disease of the vascular supply to the intestine. The occlusive disease can result from atheroma (i.e., a deposit of lipid-containing plaques an inner wall layer of an artery), thrombosis (i.e., a stationary clot attached to the blood vessel wall), or embolism (i.e., a migrating blood clot that forms a blockage) in which the collateral circulation is not adequate to maintain intestine integrity. Another common form of intestinal ischemia is ischemic colitis, in which inflammation and injury of the colon result from inadequate blood supply.
When ischemic bowel disease severely damages tissue in the intestine, the damaged tissue must be surgically removed. The remaining tissue can be sewn together, typically in end-to-end anastomosis (i.e., surgical connection of two severed tubular organ parts). Prior to resection, a surgeon must distinguish between viable and nonviable intestinal tissue. Typically, the surgeon relies on subjective visual inspection such as tissue color to determine which intestinal tissue is viable. Such a decision is often made hastily during operation. Further, such visual inspection has been shown to be unreliable in determining long-term viability of intestinal tissue.
Determining intestine viability is difficult but important for patients with ischemic bowel disease. If nonviable tissue is not removed, the result can be fatal. Removing too much intestine can also lead to severe complications. Thus, there is a need for better medical devices and systems that can determine the oxygenation state of the entire thickness of an intestinal tissue as well as other tissues. Improved devices and system can better assist doctors in determining viability of an intestinal tissue, and the doctors can make a better informed decision regarding a treatment plan for the patient. The present invention meets this and other needs.